Rhetoric is not just writing persuasively. Rhetoric is about communicating effectively. Saying you don't need rhetoric because you're an engineer is like saying you don't care if people think you're telling the truth because you're an engineer. It's absurd.
It doesn't matter if you're writing an opinion piece, a political piece, or a technical piece, if you want to structure your writing in a way that can be easily read, understood, and followed, you want to obey the principles of rhetoric.
Deliberately withholding details from a title to create more engagement based on a false impression of the content doesn't equal good rhetoric. If anything it hinges on clickbait. Calling it effective communication is the absurdity here.
I'd like you to subject your theory to the most popular (i.e., most frequently cited) engineering writings in the past 30 years. How do they exemplify such rhetoric? And how does the reader benefit from whatever rhetoric you find in them?
It doesn't matter if you're writing an opinion piece, a political piece, or a technical piece, if you want to structure your writing in a way that can be easily read, understood, and followed, you want to obey the principles of rhetoric.